Today, we add sound to radio. The University of
Houston's College of Engineering presents this series
about the machines that make our civilization run, and
the people whose ingenuity created them.

The idea that, at some point, we
had to add sound to radio may sound strange indeed. But
we did. In 1893, Nikola Tesla
sent a wireless signal across a room. In 1901, Guglielmo
Marconi sent one across the Atlantic. But neither signal
transmitted sound. Indeed, we were soon calling this new
medium wireless telegraphy, because we could send
only telegraphic dots and dashes.

Writer William Zuill tells how the little-known inventor
Reginald Fessenden solved the problem of sending
sound. Fessenden was a bright kid, born in Quebec
in 1866. He studied science, then worked as a teacher in
Bermuda. His father wanted him to be an Anglican priest.
But he was determined to work with the famous Edison.

It took him two years to get a low-level job at Edison's
Machine Works in 1885. While he worked, he studied
electricity and rose in the company. Then, one day,
Edison told him that his chemists had failed him. Edison
wanted Fessenden to learn chemistry and to invent a
flexible insulating material. So Fessenden became a
chemist.

He'd become the chief chemist just as depression forced
Edison to make cutbacks. Over the next ten years,
Fessenden taught college, he worked for Westinghouse, and
he invented. Then, in 1900, before Marconi, the U.S.
Weather Bureau went to him.

They asked if one could use radio waves to distribute
meteorological data. Fessenden managed to send data over
fifty miles. But he didn't stop there. He realized you
should be able to send more elaborate signals than Morse
Code if you could vary, or modulate, the signal's
amplitude.

The frequency of 60-hertz AC is too near the low
threshold of human hearing. He needed a high-frequency
carrier signal. He hired a GE engineer to create a
76,000-hertz generator. Then, on Christmas Eve, 1906, he
aired the first public audio broadcast from a tower in
Massachusetts. He played Handel's Largo and O
Holy Night on his violin. He sang one last verse and
finished with a Bible reading.

He went on to patent means for modulating a signal's
frequency instead of its amplitude. Think for a moment
what that meant: Fessenden had not only invented AM, he'd
also set the basis for FM.

And all this by the age of forty. The rest of his life
mired into the patent disputes that hung like a loathsome
cloud over early radio. A year later, Lee de Forest had
appropriated his key invention for transmitting AM. Edwin
Armstrong modified his theory to create practical FM. The
resulting patent miasma was still there when Fessenden
died at sixty-six.

Too bad! Fessenden had truly expressed the power of
creative renewal that Christmas Eve. Radio grew and
evolved until another Christmas Eve, sixty-two years
later. This time, NASA's Frank Borman read another message of hope as he came out
from behind the moon. And those two broadcasts remind me
that our inventions, used well, really do hold means for
raising up the human lot.

I'm John Lienhard, at the University of Houston, where
we're interested in the way inventive minds work.